[ekidd]

Very nicely done, technically. And the marketing message is both true and useful: Swimming at sea is surprisingly hard, and life jackets make a huge difference.

I was once a very strong swimmer, and back then, I tried swimming 60 feet to shore in water with choppy, 6-inch waves. I wound up repeatedly inhaling water and choking. To combat this, I tried to keep my head high above the water, which was exhausting. After 30 feet, it was clear I was in real trouble, so I called to the rowboat shadowing me 5 feet away and they towed me to shore.

Similarly, cold water will shut me down frighteningly fast—even with a wetsuit and lifejacket, I've been stunned into near immobility after less than a minute of swimming. And I'm somebody who grew up swimming in the Gulf of Maine, which can be frigid (because Cape Cod deflects the warmer Gulf Stream eastward). The actual risk here is cold shock, not hypothermia—rapid vasoconstriction in your limbs will flood your core with blood, causing your heart to work much harder to maintain circulation. It's incredibly draining.

A life-jacket will keep your head above water with minimal exertion. This means that (a) you keep breathing and (b) you remain visible to rescuers. It turns survival from an incredibly strenuous and terrifying athletic event into largely passive floating.

[nbardy]

I'm very surprised to hear how hard it was for you to swim in light chop. I grew up surfing and you paddle with your head up so you are used to craning your neck and stroke at an angle down.

When I finally starting doing some swimming in a pool I was amazed at how much easier it was to swim. Especially maintaining momentum. I also swim quite frequently without a board in open water when the waves are small, but there is still light chop and although it's surprising how slow it is I've never felt it was particularly difficult. Interesting how things work much differently transitioning the other way.

Also when you talk about wetsuit, it sounds like you haven't used a good/thick wetsuit. Or maybe this was a while ago. Wetsuit technology has been pushed really far in the last 5 years. Dry suits have always been good thanks to the military, but sports wetsuits have really progressed a lot with the explosion of the surf industry. I stay in the water easily twice as long now than I did with my first suit I bought five years ago.

[ekidd]

The chop thing was really surprising to me at the time, which is part of my point. I'd been swimming in the Gulf of Maine for years without any problem, and I didn't anticipate trouble. But the wind was really screwy and I kept aspirating salt water, and things turned bad much faster than I expected. I do agree, however, that better rough water swimming technique would have helped.

My wetsuit is good but relatively light, and I was testing it under controlled circumstances. I'm a river kayaker, a sport which involves working hard in warm air before suddenly getting plunged into a cold river. It's the sudden transition that can cause cold shock:

http://en.wikipedia.org/wiki/Cold_shock_response

http://www.seakayak.ws/kayak/kayak.nsf/0/9ABAF7D7992B8205852...

The second link mentions cases of sea kayakers who were dead within seconds of overturning. Cold shock happens much faster than hypothermia.

Fortunately, both of my misadventures happened under controlled circumstances with a backup plan. But in both cases, I was surprised and scared at how quickly I lost my ability to swim. The interactive video we're discussing actually captures the feeling pretty well.

[Swizec]

I've never felt it was particularly difficult to swim in the sea. I wonder why that is.

Two reasons come to mind:

1) Since I was a kid, sea-side vacations in the summer were common-place to the point that I actually learned how to swim in the sea. I still remember how surprised I was at the difficulty of swimming in a pool where you are much less buoyant. No salt in the water and all that.

And 2) Maybe I just haven't swam in choppy enough water. But I do remember that when waves are a certain height above your head, having a surfboard at hand suddenly makes life so much easier. Although even then I didn't feel a particular propensity to inhaling water.

edit:

3) I learned several techniques for swimming in place and resting when you're tired. If push comes to shove, you can also just lay on the water pretty much indefinitely. This one doesn't work if the water is too choppy though.

4) I probably haven't swam in a super cold sea yet. Think the coldest I've done without a wetsuit was Monterey Bay last summer where I managed to skinny dip for some half an hour or so.

[girvo]

I'm the same as you, but that's because I literally grew up on the beach in New Zealand, and swum nearly all year round. When I was older, we moved to the Gold Coast, Australia and I surfed nearly every day for my entire teenaged years; work gets in the way but I still surf as often as possible.

The one thing though, is that even with that time in the water, not having a lifejacket on a boat is absolutely foolish. The cold water really does shock your body into immobility, no matter how good of a swimmer you are. It's scary as hell.

[dbbolton]

The peripheral vasoconstriction is part of a reflex known as the mammalian dive reflex in which your heart actually slows down, rather than work harder, as soon as your face touches cold water. Muscle cramping is a direct result in the decrease in cardiac output.

https://en.wikipedia.org/wiki/Mammalian_diving_reflex

[shiggerino]

Another thing to note about mammalian diving reflex is that the nasal cavity is especially susceptible to triggering it. Which is why it's important to hold ones nose when jumping in the water to abandon ship, regardless of how silly it may look. And at this point you don't need a life jacket, you need an immersion suit.

[mrbonner]

| Swimming at sea is surprisingly hard, and life jackets make a huge difference.

I can confirm this. When I was about 16 - 17 yo (and I was very fit at the time) we went sailing with 2 of my friends on a 8 ft sailboat in Nha Trang, Vietmam. About a mile out from the shoreline the boat capsized.

We were very foolish not bringing any life-jackets. After 20 - 25 minutes trying to swim back to the shore in the afternoon's high tide and high wind one of my friend had a leg cramp. We were so lucky that we had an Igloo watercooler to tether to and relied on the wind to bring us ashore. My friend died 6 months later from cancer in California.

The other guy clung to the capsized boat and also relied the wind to bring him ashore. He ended up 5 miles from the original spot we launched the boat.

[6t6t6]

For anyone reading this.

First rule: If the boat didn't sink, never abandon it. It is relatively easy for a rescue helicopter to find a capsized boat. Not so easy to spot someone swimming. Also, you can probably manage to stay out of the water on top of the hull.

If the boat sank, stay all together next to the biggest piece of floating debris.

Source: sailing license exam. :P

[puzzlingcaptcha]

Life jacket is good, but in higher seas one of the main problems (assuming the crew remaining on board is actually competent) is visibility - consider investing into something like a dan buoy https://www.youtube.com/watch?v=BMGWk6s9G4k

[nradov]

Better visibility is helpful but even that doesn't do much in rough conditions or at night. Many of us scuba divers now carry Nautilus radios which include a GPS receiver and 2-way VHF marine radio with distress beacon. I bring mine whenever I go out on the ocean, even when I'm not diving. http://www.nautiluslifeline.com/nautilus_lifeline

[shiggerino]

DSC (digital selective calling), which that radio uses to transmit distress signals with coordinates, is an excellent but sadly under-used technology. Everyone should be equipped with it and be familiar with all the menus and options on their transceivers, and regularly test that the equipment is working by making routine calls. The problem with DSC is that the transceivers are really badly designed and downright user-hostile. The receiver usually gets a loud horn going of in their ears which only trains a reflex to reach for the silence button. It's pretty much only used for tests, and before anyone dares initiate a DSC call they call the receiving ship in advance the old-fashioned way, or they will get yelled at. When the whole point of DSC is that you merely enter the recipient's MMSI number, open a channel and just speak, without cluttering up channel 16 which is should be left for distress traffic only. Think Uhura in Star Trek. This is a huge risk to safety of life at sea that the industry urgently needs to deal with. But yes, do carry the equipment and do use it in an emergency, because it does work and it frees up yours and your rescuers' workload to worry about more important things than trying to get your coordinates across by voice.

I would also suggest getting a SART and an EPIRB. A SART is a radar beacon, which shows up as a distinctive pattern on surrounding ships' radar displays, and requires no special receiving equipment. An EPIRB is a beacon that is locatable by satellite, so that's the fastest and most reliable way to get the attention of a rescue control centre. These three technologies are part of the GMDSS (Global Maritime Distress and Safety System), which means commercial ships and emergency services are by law required to carry and use equipment to receive their signals.

[endgame]

In Australia, to call the Rescue Coordination Centre on HF, you HAVE to use DSC: http://www.amsa.gov.au/search-and-rescue/distress-and-safety...

> If a vessel wishes to conduct a radiotelephony communication with the network, it is necessary to make initial contact via a DSC call. For safety or routine messages a shift to a working frequency is normally required.

When I did my training, they pushed DSC very hard.

Nit: You mention ch16 as being for distress traffic only, but my radio handbook also lists it for carrying urgency and safety messages, and as a routine calling channel (and then you move to a working channel and get out of the way).

Also: What crazy part of the world plays clutters ch16 with music?

[shiggerino]

Yes, that is true, 16 is also for urgency and safety messages, but ideally channel 70 should supersede 16 as the routine calling channel. Of course, for that to happen the equipment has to be made actually user friendly. It would be trivial to implement the software to let the OOW simply click an AIS target on the ECDIS to have that target's MMSI entered into the transceiver and a call initiated. If ships were running on free software someone would have already done that, sent a pull request to the ECDIS software maintainer, have it pass perfectly repeatable and transparent integration test suites to make sure the patch won't make the ship go keel up, and Bob's your uncle. But for some reason people seem afraid of this proposition.

As for music, last time I heard that was in the Java sea, but Americans aren't much better, making securité calls when moving their Bayliners, or the USCG with their incessant babble about irrelevant things.

[endgame]

Not everyone's got AIS and ECDIS though. The places where I trained really pushed DSC for fishing and recreational use, by making it relevant to the little guys too: "If you'd just found a good fishing spot or a nice quiet place, why would you go blabbing to everyone about it on ch16? Call your mate up on DSC instead." They also made a point of telling people to spend that bit extra to get a radio that doesn't suck. Buying a cheap transceiver and having to input a MMSI using up/down/enter/back is really annoying and doesn't help take-up at all.

Speaking of AIS, did you see this thing from a couple of years back: http://blog.trendmicro.com/trendlabs-security-intelligence/v... ?

[dognotdog]

I agree that the DSC situation is terrible. And particularly around Italy, people play music on CH16, so whichever radio one has, DSC or analog, it's a tough call. Then again, the mediterranean isn't very cold, so it's not a matter of minutes, unless you fell into a swarm of jellyfish.

Also, an AIS PLB, if the boat is equipped with AIS, is great, it's no bigger than a radio, and theoretically also triggers an alarm on any AIS capable vessel nearby. Without a life jacket, getting found again on the open sea in anything but calm conditions is difficult to imagine, considering how terribly hard it is to locate a head barely above water in the waves.

[satori99]

I have had a tow line break, and lost an entire tender in a calm sea. As soon as you lose eye contact, it's almost as good as gone.

And everytime I have sailed in a blue water race, the entire crew wear self inflating harnesses that also contain a radio, gps, knife, dye, etc.... and often also a high vis swimmers cap. And the harness never comes off. Even while sleeping.

[dzhiurgis]

It's 2015. Just get a life jacket with integrated EPIRB.

[Tuna-Fish]

> Similarly, cold water will shut me down frighteningly fast—even with a wetsuit and lifejacket, I've been stunned into near immobility after less than a minute of swimming.

As someone who routinely goes swimming in a hole cut in ice with the water temperature typically around 1C, this sounds weird. I suppose it's a reaction you can teach your body to not have?

[mjlee]

You can acclimatise to it but cold shock response is a very real thing. The first minute is the most important - you're lucky to survive long enough to die of hypothermia.

[Tuna-Fish]

The typical way people swim among ice is to first just dip yourself, get up from the water, hang out for like a minute, then go back in there. I wonder if this has something to do with it?

[kiiski]

You don't get your face/head wet when ice swimming, I suppose?

[Tuna-Fish]

I generally don't dip my ears below the surface because ear infections are a risk, but I certainly get my face wet.

[frobozz]

> A life-jacket will keep your head above water with minimal exertion.

With no exertion, depending on conditions. Lifejackets should be able to support an unconscious casualty.